Patent document 1 describes an example of a vehicle door lock device known in the prior art. The door lock device includes an actuator that pivots an output lever from a neutral position in a lock direction and an unlock direction and pivots the output lever back to the neutral position with a motor, which is capable of producing forward and reverse rotation, by means of a reduction gear mechanism. When the output lever moves in the lock direction and the unlock direction, a lock-unlock lever moves to a lock position for locking a door and an unlock position for unlocking the door. The door lock device further includes a lock-unlock operation switch, a childproof operation switch, an outside handle operation detection switch, a lock actuation detection switch, an unlock actuation detection switch, a neutral detection switch, and a control unit. The outside handle operation detection switch detects the operation of an outside handle arranged outside the vehicle. The lock actuation detection switch detects that the lock-unlock lever has reached the lock position. The unlock actuation detection switch detects that the lock-unlock lever has reached the unlock position. The neutral detection switch detects that the output lever has reached the neutral position. The control unit is connected to the motor and the switches. When the lock-unlock operation switch, which is arranged in the passenger compartment, undergoes a lock operation or an unlock operation, the control unit activates the motor to pivot the output lever in the lock direction or the unlock direction. When the lock activation detection switch or the unlock activation detection switch is activated, the control unit produces reverse rotation with the motor until the neutral detection switch is activated and returns the output lever to the neutral position. When the childproof operation switch, which is arranged in the passenger compartment, undergoes a lock operation, the control unit activates the motor to pivot the output lever in the lock direction. When the lock activation detection switch is activated, the control unit deactivates the motor to stop the output lever at a position that prevents the lock-unlock lever from moving to the unlock position. In this state, when the outside handle operation detection switch is activated, the control unit activates the motor to move the lock-unlock lever to the unlock position. This structure allows for a single motor to perform door lock and unlock operations and a childproof operation, which disables unlocking from inside the vehicle and enables unlocking from outside the vehicle.
In patent document 1, the state of each lever is detected in detail by the corresponding switch, and the motor is controlled to stop each lever. This allows for the motor to take two states (operations). Thus, the necessary number of switches increases, and the electrical structure becomes complicated. Further, when the lever state (position) is electrically detected with each switch, there is a tendency for variations to occur depending on the situation. The may produce operation failures in each state.
Patent Document 1
    Japanese Examined Patent Publication 7-26502 (FIGS. 1 and 5)